In recent years, particularly from a viewpoint of protecting the global environment, expectation for a solar cell as a next-generation energy source converting solar energy into electric energy rises drastically. There are various types of solar cells, such as solar cells employing a compound semiconductor, organic material, or the like. Currently, a solar cell employing silicon crystal is on the main stream.
Currently, the most manufactured and commercially available solar cell is a double-sided electrode type solar cell having a configuration with an n-electrode formed on a surface on a side of receiving an incident sunlight (light receiving surface) and a p-electrode formed on a surface opposite to the light receiving surface (back surface).
Further, development of a back electrode type solar cell having an n-electrode and a p-electrode formed only on a back surface of a solar cell without forming an electrode on a light receiving surface of a solar cell is also promoted.
For example, PTD 1 (Japanese Patent Laying-Open No. 2009-88145) discloses a technology of connecting a back electrode type solar cell with an interconnection sheet. According to PTD 1 (Japanese Patent Laying-Open No. 2009-88145), the back electrode type solar cell and the interconnection sheet are connected by the following steps of:
(1) applying solder coating to an electrode portion by immersing the back electrode type solar cell in an Sn—Bi solder tank;
(2) applying an acrylic adhesive to a portion other than an electrode of the back electrode type solar cell by screen printing;
(3) providing the back electrode type solar cell on an interconnection sheet; and
(4) applying heat-pressure bonding between the back electrode type solar cell and the interconnection sheet.
Accordingly, in PTD 1 (Japanese Patent Laying-Open No. 2009-88145), the electrode of the back electrode type solar cell and the interconnection of the interconnection sheet are electrically connected by Sn—Bi solder, and the back electrode type solar cell and the interconnection sheet are mechanically connected by bonding with use of an acrylic adhesive.